Antimicrobial Coatings...Silver Bullet or Snake Oil?

Concern about microbes and the risks they bring had already been increasing over the past 20 years, but the pandemic created even more heightened awareness by government, business and the general public of the threat. Understandably paint makers want to do the best they can to address this issue and a wide range of antimicrobial coatings are  currently available with the likelihood  that many more will follow. Are they the answer to a major health problem? Do they make no difference? Or could they make things worse?

Q: What do we mean by microbes? 

A: This is a very broad  and general term for all the life forms that are so small that a single one is invisible to the naked eye, It includes bacteria, fungi, yeasts and moulds, some microscopic multi celled animals and plants, and also includes viruses that most scientists do not consider to be alive in the accepted sense.

Q: Where do we find microbes? 

A: Quite literally they are everywhere. In the air, in water, in soil and of course in and on our bodies. There are approximately 30 trillion cells in a normal human body, those cells are in turn home and host for 300 trillion microbes, outnumbering our own cells by 10 to one. They do sometimes cause illness and disease but their presence is essential for survival. Without microbes... there would be no life on earth.

Q: If they are so vital isn’t it risky to try to kill them? 

A: Actually yes, it can be very risky because we are in balance with the microbes that are here now. Our immune systems cope with the current species remarkably well, but if they change or mutate significantly (sometimes even slightly) they can become dangerous variants or mutants. This is why antimicrobial products and their use is a highly regulated field.

Q: Does that mean antimicrobial paints are a bad idea? 

A: Absolutely not paint and coatings can be a very important part of hygienic practices. But it is vital that the claims made for them improve hygiene and do not increase risk or encourage bad practices.

Q: How can an antimicrobial paint encourage bad practice? 

A: Because they need to be used as part of good hygienic practice not as a substitute for it. It is essential that antimicrobial surfaces are  not regarded as a magic bullet to microbes. In the UK several years ago antimicrobial food chopping boards gained notoriety and newspaper coverage because people were putting rotten or rotting food onto them and thinking that the chopping board would reverse the rot!

Q: How should antimicrobial paints be used properly?

A: If used in situations where hygiene is paramount such as food preparation and healthcare. antimicrobial coatings can add another level of safety by “mopping up” small areas of surviving microbes in “missed areas” that exist after cleaning. They also work well in hard to access areas such as HVAC ducting etc, where cleaning is very difficult, and where a background kill is a real bonus

Q: That sounds great should we use these paints everywhere.?

A: I would say no. Microbes generally are not our enemy, so we should control them only in areas of particular concern. At their best these coatings only work when in direct contact with microbes. This means that even thin layers of soilage can insulate “bugs” from the active paint, ie they may not make contact with the active ingredient, and so can survive and grow. Antimicrobial paints only work as part of a complete suite of hygienic practices.

Q .  Do you think we will see more antimicrobial paints in the future, designed to combat things like flu and covid?  

A: No I don’t. it is illegal in most countries to make disease claims for hygiene products, so “New anti-flu the paint that keeps your family free from influenza” is very unlikely to be on the shelves any time soon. In addition regulators are putting huge pressure on manufacturers to remove anti-microbial materials (preservatives) from their paint.

About the Author  Stephen Falder trained as a microbiologist at King’s College London. He is  an owner of HMG Paints Ltd the UK’s largest private specialty paint maker, and is the inventor of the antimicrobial technology Byotrol & founder director of Byotrol Plc. He is the Secretary General of  the Nova Paint Club, an industry group of some of the world’s most successful Independent coatings manufacturers.